This was great -- one of the early classics of hard SF, about the sorts of very different creatures that you'd get on a fast-spinning, heavy planet. (So it's much like "Dragon's Egg", but written in 1953 rather than 1980 -- not that you'd realise!)
I should probably just buy the entire SF Masterworks series, since all of them that I've read so far have been excellent...
ISBN 0575070943. Search for this book on Wikipedia or isbn.nu.